Compare the relative heights and sizes of what you're drawing or you tend to get massive bridges or hulls with no draught. Bare in mind a deck is generally between 17-21 pixels in height so make sure you have enough room in your hull for accommodation and machinery.
The sonar bulb that you depicted was really not very hydrodynamic and was full of pixel errors (double blacks etc) The solid sides on the bow are somewhat higher than would normally be seen, at least by my eye so they should be lowered accordingly (the green pixels in my illustration denote where the actual deck surface is)
Make sure your design has enough draught for the size of the vessel or it would/will suffer from a lack of stability and may well capsize.